Method of dyeing keratinous fibers



Patented Mar. 21, 1950 METHOD F DYEING KERATINOUS FIBERS Edwin E. Michaels, Stamford, Conn., and Bernard Berk, New York, N. Y., assignors to Lawrence Richard Bruce, Incorporated, Stamford, Conn, a corporation of Connecticut No Drawing. Application April 6, 1944, Serial No. 529,860

2 Claims.

This invention relates to methods or media for dyeing keratinous fibres such as hair, wool, fur, feathers, etc, being particularly directed to the dyeing of these resistant fibres at low temperatures, as for example, in the range of human body tolerance.

Broadly, it is an object of this invention to provide for the dyeing of a resistant fibre of the character and within the range outlined aforesaid, by applying with and as a carrier for the dye, a composition incorporating respectively a medium, being or having the properties of a weak acid having the function of effecting a primary opening of the fibre, and a Water soluble organic medium functioning only in the presence of the first medium to effectuate a secondary opening of the fibre, thereby to increase the permeability of the fibre for the dyestufi.

Up to the present time, it has been known that fibres, such as wool, may be dyed upon treatment with dilute solutions of strong acids at high temperatures or concentrated solutions of certain weak acids at room temperature, but in either event, the conditions of these treatments make them impractical for such use with resistant fibre of the class in the temperature range aforesaid, by virtue of their corrosive action in proximity of human tissue.

In the prior art, particularly in the dyeing of textiles such as cotton or wool, certain water soluble organic compounds classified as dye assistants have been used to increase the solubility of normally slightly soluble dyes but such effect is of no avail in the treatment of keratinous fibre within the required body temperature range, in view of the resistance of the protein formation thereof to penetration.

We have found that weak acids of relatively low concentration and having a low dissociation constant when applied to a keratinous fibre at body temperature will react with the fibre to a high degree. This phenomenon may be explained by the Proctor-Wilson theory of swelling. Use has been made of the high degree of reaction of weak acids with keratinous fibres to a limited extent for imparting a surface coloration thereto by reacting dyestuff with these acids for absorption on the surface of the fibre. However, this limited opening of the fibre in the presence of dilute solutions of weak acids per se is not enough to permit the entrance of dye molecules to the fibres and the end product obtained by this step is a temporary soap fugitive surface coloration.

We have, as an object of this invention discovered that use can be made of the phenomenon involving the reaction of the weak acid with the keratin, for slightly opening the same to make accessible to the fibre a second group of reagents, namely, water soluble compounds of a class, which under the above condition acting on the slightly opened fibre by greatly swelling the same disrupting the secondary linkages thereof and further opening its pores to such an extent that normally non-substantive dye will be carried into the fibre for reaction therewith and deposit therein, to thereby dye the cuticle and cortex of the fibre and permanently coloring the keratin in such a manner as is useful for commercial processes.

The acid medium referred to above can be defined as a non-reducing weak acid or acid salt having a dissociation constant of 10- to 1G As examples of acid media having these properties which we have found useful in our method of dyeing, acetic acid, formic acid, propionic acid, tartaric acid, disodium hydrogen phosphate, malic acid, lactic acid, all of which are representative of the class defined aforesaid. Effective concentration of these acids or acid salts useful for dyeing purposes, in accordance with our discovery is from 1 to 15%.

Among the class of water soluble organic compound, we have found that the most useful in the effectuation of our procedure are: urea and its derivatives such as methyl-urea, propyl-urea, thio-urea, etc.; carbamates and their derivatives, such as urethane and propyl-carbamate, etc. amides and their derivatives such as formamide, acetamide, propionamide, etc.; salts of amines, such as guanadine, amylamine and butylamine, salts, etc; nitro-paraffines and their derivatives, such as nitro-methane, 2-nitro-1-propano1, 2- nitro-l-butanol, etc.; primary aliphatic alcohols, such as methyl, ethyl and iso-propyl alcohol; phenols, such as resorcinol, etc.; catechols, etc. The aforesaid water soluble organic reagents are usually applied in concentrations of 10 to 60%.

Following is a representative example of a treatment solution applicable in accordance With our invention to dye keratinous fibre, for instance, human hair, to a medium brown color.

We dissolve a mixture of dyes of the following proportion:

.6 gr. D & C Black No. 1 .5 gr. D & C Brown No. 1 .4 gr. External D & C Red #13 We may, for the purpose of increasing the ease of dissolving the dyestufi and contributing to its stability in the acid solution incorporate as part of the solvent a wetting agent such as those readily purchasable on the market under various trade-marks and of 1% benzoic acid.

Although in the aforesaid example we have indicated the use of a single water soluble organic reagent in association with the weak acid, we may apply an intermixture of more than one such reagent, as for example, we have successfully applied the following mixture in association with the dyestufi and the acid of Example 1. In lieu of urea we have used 20% urethane and ethyl alcohol.

Although the nitro-paraifine series listed among the water soluble organic compounds are all effective as swelling agents acting on Opening fibres and are useful in association with weak acids under our procedure aforesaid, certain members of this group, namely Z-nitro-l-propanol and 2- :nitro-l-butanol, exemplifying nitro-paraifines having a labile hydrogen have been found to possess the properties by themselves of sufficiently opening keratin fibre to an extent that normally non-substantive dyes will be carried into the fibre for reaction therewith and deposit therein.

Various changes and modifications may be made to the details of the invention without departing from the broader spirit and scope thereof, as set forth in the following claims.

We claim:

1. A method for imparting color to keratinous fibre at body tolerance temperatures, with dyes normally non-substantive thereto, which comprises treating the fibre with reagents incorporating a dye of the class aforesaid, said reagents consisting of dilute acetic acid having the characteristics of opening the fibre, and urea having the property of greatly swelling the keratin fibre and disrupting the secondary linkages thereof onl in the presence of and upon opening of th fibre by said acid, to increase the permeability of the fibre to the extent that the dye aforesaid penetrates and diffuses through the cuticle of the fibre.

2. A method for imparting color to keratinous 4 fibre at body tolerance temperatures, with dyes normally non-substantive thereto, which comprises treating the fibre with reagents incorporating a dye of the class aforesaid, said reagents consisting of dilute acetic acid having the characteristics of openin the fibre, and a mixture of urea and alcohol having the property of greatly swelling the keratin fibre and disrupting the secondary linkages thereof only in the presence of and upon opening of the fibre by said acid, to increase the permeability of the fibre to the extent that the dye aforesaid penetrates and diffuses through the cuticle of the fibre.

EDWIN B. MICHAELS.

BERNARD BERK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,886,412 Martin Nov. 8, 1932 2,018,436 Brandt Oct. 22, 1935 2,116,521 Kritchevsky May 10, 1938 2,163,043 Kritchevsky June 20, 1939 2,183,754 Schlack Dec. 19, 1939 2,185,467 Kritchevsky Jan. 2, 1940 2,228,369 Schoeller Jan 14, 1941 2,238,949 Schlack Apr. 22, 1941 2,261,094 Speakman Oct. 28, 1941 2,303,932 Guild Dec. 1, 1942 FOREIGN PATENTS Number Country Date 44,949 France May 1, 1935 (1st addition to No. 771,270) 453,559 Great Britain 1935 828,616 France May 24, 1938 OTHER REFERENCES Jones and Mechan, Dispersion of Kcratins, Archives of Bio-Chemistry, vol. 2 (1943), pages 209-223.

Goodall Theory of Wool Dyeing, Soc. of Dyers and Colourists, February 1937, pages 5056. 

1. A METHOD FOR IMPARTING COLOR TO KERATINOUS FIBRE AT BODY TOLERANCE TEMPERATURES, WITH DYES NORMALLY NON-SUBSTANTIVE THERETO, WHICH COMPRISES TREATING THE FIBRE WITH REAGENTS INCORPORATING A DYE OF THE CLASS AFORESAID, SAID REAGENTS CONSISTING OF DILUTE ACETIC ACID HAVING THE CHARACTERISTICS OF OPENING THE FIBRE, AND UREA HAVING THE PROPERTY OF GREATLY SWELLING THE KERATIN FIBRE AND DISRUPTING THE SECONDARY LINKAGES THEREOF ONLY IN THE PRESENCE OF AND UPON OPENING OF THE FIBRE BY SAID ACID, TO INCREASE THE PERMEABILITY OF THE FIBRE TO THE EXTENT THAT THE DYE AFORESAID PENETRATES AND DIFFUSES THROUGH THE CUTICLE OF THE FIBRE. 